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Perplexed Tick-trefoil (Desmodium perplexum)

Life history

Species overview

Perplexed Tick-trefoil (Desmodium perplexum), a Wisconsin Special Concern plant, is found in open forests and savannahs, or other dry upland habitats. Blooming occurs July through August; fruiting occurs summer through fall. The optimal identification period for this species is mid-summer through early fall.

Synonyms: Desmodium paniculatum var. dillenii, D. dillenii


  • Distinguishing characteristics: Plant erect and branching occasionally, with petioles at least .5 cm long. Both stem and petiole are pubescent with wavy or straight hairs and a fine underlayer of puberulence. Most likely to be confused with D. glabellum, which has hairs that are hooked on the stem and petiole and a strong reticulated vein network on the lower surface of the leaflets, or panicled tick-trefoil (D. paniculatum) which has longer leaflets (3 to 7 times as long as wide).
  • Flower characteristics: White to pinkish-purple pea-like flower, usually 6 to 7.5 mm in width, with two lateral petals and a keel. Borne on panicles up to 5 cm long
  • Fruit characteristics: Pod flat with 2 to 4 segments that are triangular or unevenly diamond-shaped, and covered in hairs that stick to fur and clothes.
  • Leaf characteristics: Alternate, trifoliate leaves with oblong-lanceolate leaflets. Leaflets are 1 to 3 times as long as wide. Petioles of the middle leaves (sometimes all) are at least 4 mm in length, and equal to or greater than the width of the terminal leaflet.


  • Blooming phenology: July through August
  • Fruiting phenology: summer through fall
  • Optimum time to identify: The optimal identification period for this species is mid-summer through early fall


  • Growth form: Forb-erect
  • Vegetative reproduction:
  • Life cycle: Perennial
  • Comments: A pioneer species that does well with some disturbance.

State status

Status and Natural Heritage Inventory documented occurrences in Wisconsin

The table below provides information about the protected status - state and federal - and the rank (S and G Ranks) for Perplexed Tick-trefoil (Desmodium perplexum). See the Working List Key for more information about abbreviations. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. The map is provided as a general reference of where this species has been found to date and is not meant as a range map.

Documented locations of Desmodium perplexum in the Natural Heritage Inventory Database as of July 2015.

Summary Information
State StatusSC
Federal Status in Wisconsinnone
State RankS2S3
Global RankG5
Tracked by NHIY

Habitats and landscapes

The Natural Heritage Inventory has developed scores indicating the degree to which each of Wisconsin's rare plant species is associated with a particular natural community or ecological landscape. This information is similar to that found in the Wildlife Action Plan for animals. As this is a work in progress, we welcome your suggestions and feedback.

General habitat information

  • Habitat description: Found in open forests and savannahs, or other dry upland habitats.
  • Soils: loam, clay-loam or rocky

Natural communities

This table lists the natural communities that are associated with Perplexed Tick-trefoil. Scores for natural community associations are: "significant" association (score=3), "moderate association" (score=2) or the species can be present but is only weakly associated with the community (score=1).

Ecological landscapes

This table lists the ecological landscape association scores for Perplexed Tick-trefoil. The scores (3=High, 2=Moderate, 1=Low, 0=None) also correspond to the map.

Map of the Ecological Landscapes of Wisconsin.

Species guidance

The Endangered Resources Program has developed avoidance measures and management guidelines for plants on the Natural Heritage Working List. These are a work in progress, and we welcome your suggestions and feedback. Sources used in developing this information can be found here.

Avoidance measures

These are specific actions designed to avoid "take" (mortality) of this species.

  • No avoidance measures have been developed for this species.

Management guidance

Management guidelines are additional considerations that may help maintain or enhance habitat for this species

  • No guidance has been developed for this species.


Perplexed Tick-trefoil Photo.

Scanned specimen courtesy of Wisconsin Herbarium

Support for Wisconsin's rare plant information has been provided by the Division of Forestry, the Endangered Resources Fund and the Wisconsin Rare Plant Preservation Fund. To donate, visit the Natural Resources Foundation of Wisconsin [exit DNR].

Last revised: Wednesday, May 05, 2021
Southwest Savanna Southern Lake Michigan Coastal Western Coulees and Ridges Southeast Glacial Plains Central Sand Hills Central Lake Michigan Coastal Central Sand Plains Northern Lake Michigan Coastal Northern Lake Michigan Coastal Northeast Sands Western Prairie North Central Forest Northern Highlands Northwest Lowlands Northwest Sands Northwest Lowlands Superior Coastal Plains Forest Transition